1. Field of the Invention
One embodiment of the present invention relates to a method for forming a microcrystalline semiconductor film, a method for manufacturing a semiconductor device including the microcrystalline semiconductor film, and a display device.
In this specification, a semiconductor device means all types of devices which can function by utilizing semiconductor characteristics, and a display device, an electro-optical device, a photoelectric conversion device, a semiconductor circuit, and an electronic device are all semiconductor devices.
2. Description of the Related Art
As one type of field-effect transistor, a thin film transistor whose channel region is formed in a semiconductor film which is formed over a substrate having an insulating surface is known. Techniques in which amorphous silicon, microcrystalline silicon, or polycrystalline silicon is used for the semiconductor film where the channel region is formed in the thin film transistor have been disclosed (see Patent Documents 1 to 5). A typical application of the thin film transistor is a liquid crystal television device, in which the thin film transistor is practically used as a switching transistor in each pixel in a display screen.
In addition, a photoelectric conversion device has been developed in which a microcrystalline silicon film, which is a film of crystalline silicon capable of being formed by a plasma CVD method, is used as a semiconductor film having a function of photoelectric conversion (for example, see Patent Document 6).